As virtualization technologies develop rapidly, network functions virtualization (NFV) gradually gains attention from people. In an NFV system, a VNF instance can run on a general-purpose physical device by implementing instantiation of a virtualized network function (VNF), thereby implementing a dedicated function of a network element device in a network by using the general-purpose physical device.
A virtualized network function manager (VNFM) exists in the NFV system, and can perform life cycle management on a VNF in the NFV system, for example, perform an operation such as instantiation, scale-out, or termination on the VNF in the NFV system. When load of a VNF in the NFV system exceeds a load threshold because of an increase in a user quantity or data traffic of the VNF, the VNF can initiate a scale-out operation. That is, the VNF determines, according to the increased user quantity or data traffic, resources that need to be added to the VNF, and sends a scale-out request message to a MANO, to request the MANO to scale out the VNF, that is, to request the MANO to allocate, to the VNF, the resources requested to be added to the VNF.
In the NFV system, multiple VNFs may be members of a same network service (NS), that is, the multiple VNFs are functionally associated with each other. After a VNF is scaled out, the VNF generates more data traffic because a service processing capability of the VNF is enhanced. Therefore, if a service processing capability of a VNF directly associated with the VNF is not sufficient for processing in time the data traffic generated by the VNF, the VNF has service impact on the VNF directly associated with the VNF, and a service call loss is caused to the VNF directly associated with the VNF.